View Full Version : Newbie with a Lm1 , AFR results
ok folks, just trying to learn a little here, i have a lm1, set it up and set about going for a drive 30 mins ago.
I was told by the previous owner the fueling was setup for around 14psi. ive set the actuator to just under 1 bar of boost based on carb bottom.
My results are below,
Idle sat between 14.2 - 13.8 although occasionaly went into low 13s however my r5 hasnt got the smoothest idle.
Cruising off boost it was reading around the 14.7 mark.
W.O.T was reading around 12.7 , and occasionaly between gears jumping into low 13's for a split second but then settling back to around 12.7.
Now please bear in mind im new to this, and just trying to learn as i do with everything else (welding/painting etc)
Ive looked at the article on afr's and believe my results above appear to be ok, however is there room for improvement.
I personally would richen it up a little at wot to 12.1, keep it nice & reliable.
to be fair id like to up the boost a bit aswell at the same time, just searching these boards now to see how best to go about doing that.. , cheers for the advice tho dude, i thought it may be a little lean
If your upping the boost its worth investing in a mechanics stethoscope to listen for det aswell :)
aight dude,
Would 18psi, with a t2/t25 which is what i think mine is be a reasonable target..
going to whip the carb off tomorrow and measure up the jets i think
can i also ask if this will be ideal..
Its a micro drill bit pack with a hand driven drill .. or would i be better with electirc ?
http://cgi.ebay.co.uk/MICRO-ARCHIMEDES-CRAFT-DRILL-20-TINY-BITS-UK-STOCK-/360281121178?pt=UK_Crafts_JewelleryMaking_GL
That will do the job. I hand drill most of my jets, i use a pikey old chuck that i hacksawed off an old hand drill.
SCHWARTZ
20-08-2010, 21:13
you could probably do with a drill bit kit that is slightly bigger. if you could get a 20 piece kit that started at 1mm that would be better for you as youre not going to use much under 1mm;)
Well i picked up a drill bit kit and measured up the jets currently in there.
A/c - 1.2
main - 1.2
2nd stage - 1.2
1st state - 1.0
from my understanding the carbs standard other than the 1.2 2nd stage.
Now i plan to run 18psi if possible, why that figure ? just because i hear it a lot and it has a catch to it.
now am i best to set it to 18psi, drive it and see what the afr's tell, or would i be better off drilling out the 2nd stage to 1.3, driving it at 14psi and getting it to run correctly at that.
or failing that should i get hol of a small a/c first and see how that goes?
Just wondering what the general order of things are thats all.
SCHWARTZ
24-08-2010, 20:11
get smaller a/c .9 something like that (drop a blob of solder in it, when off the carb:laugh: and then re-drill)
prob need a slightly bigger main like 130 poss
then like you said is just a case of driving it and see what the results are and go from there.
dont open second stage up yet as it it hard to make it smaller again.
also may be worth buying a carb rebuild kit as it will be coming apart a lot if you havnt done all ready;)
Drop a 1.00 a/c in mate, a spare 1st stage enrichment jet will do. If you need even more fuel go for .9 a/c or 1.3 2nd stage.
car.crash
24-08-2010, 21:04
when drilling the jets with the tiny bits use one of these as it makes the job easyer :)
http://cgi.ebay.co.uk/Archimedes-Archimedean-Drill-Jewellery-Modelling-/170521112261?pt=UK_Hand_Tools_Equipment
dangerous dave
24-08-2010, 21:09
18 psi on a t2/t25 should be a fair bit of boost and see you some good power that can be enjoyed whatever roads your on..
more boost or laggy t28's need a clear run cuz your shifting tarmac at some rate..:devil:
cheers for the advice, was waiting for your post, ive actually already soldered and drilled a jet to 0.9, albeit a bit on the piss, not sure if that will effect anything, however ill try a 1.0 jet first as ive gota few kicking about spare.
I will keep this thread updated, 1 reason so you guys can keep me on the right track, and second reason so hopefully people can find it at a later date and learn from it.
quick update,
id already prepared the 0.9 ac jet so i dropped that in , and upped the boost to 1.3 bar 18/19 psi.
Idle was 13.9 ( i manged to get a smooter idle by richening it up a bit.
crusing was 14.5's
w.o.t was 11.5
based on this my next thought was going to be going to a 1.0 ac jet
seem reasonable ?
well i tried it with a 1.00 acc jet and it ran very lean , high 13's / low 14's.
I presume then thats all i can do with the acc jet and now i should be looking at maybe using the 1.00 acc jet and going larger on the 2nd stage ?
SCHWARTZ
28-08-2010, 19:34
or a slightly larger main poss:confused:
Yep, time to start messing about with the 2nd stage by the sounds of it.
Markey Mark (BD)
28-08-2010, 19:48
or a slightly larger main poss:confused:
No need for a larger main jet at 18psi mate, i'm still using a standard 1.2 main on the campus
Djinuk - i'd be looking at the second stage jet, go up in size the smallest amounts you can just to decrease the chance of drilling it too big.
SCHWARTZ
28-08-2010, 19:58
:ashamed::laugh:
sweet will do, ive gota couple of carbs so worst case if i do is i just fling another on.
surprised at how much diff the .1ac did, for the min ive dropped the .9 back in, but got the hesitation issues whenever i go from 3rd to 4th at full chat.
Ill drill out 2nd stage 2moro, drop the larger acc in and update with my findings.
Well , ive drilled the 2nd stage to 1.3, however saying that it litrally took about 2 seconds, so at first i thought id incorrectly measured the 2nd stage and that it was already 1.3, however when removed the drill bit there was swarf on it so it definatly removed some material.
Anyways, running the 1.0acc and 1.3 2nd stage im getting wot afrs of 11.7, Im going to see if i can possibly drill my 0.9acc to 0.95, and see how it fairs.
I guess this is where the tuning becomes much more fine.
Markey Mark (BD)
29-08-2010, 16:44
I guess this is where the tuning becomes much more fine.
:agree: The fine tuning is the key bit mate to getting them right, looks like you got it going in right direction now though, 11.7 isn't too bad, little rich but almost there. ;)
Matt Cole
29-08-2010, 16:45
Id be happy with 11.7 at WOT. Is that at 18psi?
yea was 1.3 bar which i thinks a little over 18psi, really enjoying it now though..
I did have one problem, i had a vacume hose i left off on the carb top, i hit boost and it miss fired, i let off and tried again.. so i pulled over, realised my error, popped it on and all sorted..
Any chance any damage was caused, seems to be fine :).
Just searching the boards and it seems a lot of fives seem to make quite a bit more power by running just slightly leaner.
I spoke to my friend whos going to tap me a thread in my spare carb body to accept jets into the 2nd stage , so that its a little easier to tune..
still getting the hestitation between 3rd and 4th when at full chat. Going to check the fuel jet tomorrow with a 5mm drill bit, i presume it should be set so that it begins pushing the rod when the throttle flap is 5mm open?
Also nothing that my light crusing afrs are now in high 12's , is there any way to lean this off a bit?
Does it go rich or lean when you get the hesitation ? Does it bog down or more missfire?
I forget what I had on light throttle now so can't help with that.
Also have you checked the fuel pressure, maybe the pump is on it's way out, blocked filter ? There are 2, one inside the brass carb feed on the carb & the main fuel filter.
pump and filter are both new items, im not sure what the fueling does yet as i always 4get to look when it does it, could do with a passenger to read it ideally for me.
Ill check the carb filter, its a definate bogdown though not a missfire, dosent kangaroo or anything.
just a note to add..
in any situation do people make the main jet smaller than standard and then work on the on boost conditions using the acc/2nd stage, reason i ask is my fueling seems to of crept up quite rich on gentle crusing.
on light throttle my afrs are in the high 12's
When you say light throttle are you on boost? a couple of psi activates the 1st stage.
Its hard to lean off the cruise/midrange when using a smaller air corrector, you might have to live with it.
Matt Cole
01-09-2010, 13:18
on light throttle my afrs are in the high 12's
This is the problem i had with mine now that i remember. I think i messed about with the 1st stage enrichment screw (behind the alloy ball bearing) shimmed it and adjusted it to fuel on circuit to suit when the boost came on. I then altered the main jet to suit the part throttle / cruising AFR's untill they sat at low 14's. When on WOT, second stage would come on spot on and sit at high 11's.
Its all coming back to me this carb malarkey!!:D
ill hook up the lm1 tonight and try for some more accurate results as it maybe just as the turbo begins spooling..
Im familiar witht the 1st stage jet , within the second part of the carb that comes off, however im not familiar with the ball bearing etc.
giving my carb a fresh rebuild tonight, then going to focus on tuning it a bit more, anyone fancy offering soem insight on this small ball bearing etc
This is the problem i had with mine now that i remember. I think i messed about with the 1st stage enrichment screw (behind the alloy ball bearing) shimmed it and adjusted it to fuel on circuit to suit when the boost came on. I then altered the main jet to suit the part throttle / cruising AFR's untill they sat at low 14's. When on WOT, second stage would come on spot on and sit at high 11's.
Its all coming back to me this carb malarkey!!:D
just re-read this and went to my haynes carb manual and it makes sense.. so first stage activates when reaching a certain boost (small amount) however as mine seems to be activating to early and running to rich when on light throttle i can increase the pressure it takes to open stage 1 jet, by using a couple of washers on the spring.. and then see how it fairs..
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